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Evaluation of wood treated with copper-based preservatives for Cu loss during exposure to heat and copper-tolerant Bacillus licheniformis
1999 - IRG/WP 99-20155
Copper-based wood preservatives need to be effective against exposure to all types of microorganisms. Wood treated with six copper-based preservatives was exposed to 121°C and 20 psi pressure for 15 minutes under standard autoclave conditions and the copper-tolerant bacterium, Bacillus licheniformis CC01, for 10 d at 28°C and 150 rpm. Sixteen to 37 percent of the copper was released from the wood during autoclaving, with copper citrate demonstrating the highest percent loss. Forty-four to 82 percent of the copper remaining in the samples following autoclaving was removed during exposure to the bacterium in liquid culture; copper naphthenate in oil and ACQ-D had losses of eighty percent or greater of the remaining copper. The bacterium removed as much or more total copper in 4 of 6 gas-sterilized samples (85-94%) than the cumulative effects of steam-sterilization and the bacterium on treated samples. Copper loss from in-service treated wood compromises the efficacy of copper-based wood preservatives.
D M Crawford, C A Clausen

Semi-Solid State Bioremediation of CCA-Treated Wood Using Malted Barley as a Nutrient Source
2002 - IRG/WP 02-50184
Bioremediation processes for recovery and reuse of CCA-treated wood invariably increase the cost of any secondary products manufactured from the remediated fiber. Microbial remediation using either bacteria or fungi has been shown to remove heavy metals from CCA-treated southern yellow pine (SYP). In a two-step remediation process utilizing oxalic acid extraction and the metal-tolerant bacterium Bacillus licheniformis, 70-100% of the copper, chromium and arsenic can be removed from CCA-treated SYP, but the liquid culture medium used to support the bacterial growth renders this process costly. Processing costs could be partially offset if the culture medium were replaced with an industrial by-product. In this study, an abundant by-product of the brewing industry, malted barley, was evaluated as a replacement for commercial nutrient broth in the bioremediation process for CCA-treated SYP. Malted barley’s high moisture and nutrient content should support bacterial growth. When malted barley was substituted as a growth substrate for nutrient broth, it was discovered that either the culture inoculum or wood itself provided sufficient nutrients for the growth of B. licheniformis. Seventeen percent of the copper and 15% of the arsenic was removed from an aqueous slurry of CCA-treated SYP following bacterial remediation with B. licheniformis. When oxalic acid extraction preceded the aqueous bacterial culture of CCA-treated SYP, 21% Cu, 54% Cr and 63% As were removed. Incidentally, malted barley acted as a biosorbent, removing heavy metals from the liquid culture upon their release from CCA-treated SYP.
C A Clausen

Enhanced removal of CCA from treated wood by Bacillus licheniformis in continuous culture
1997 - IRG/WP 97-50083
A gram positive, spore-forming bacterium, which was isolated from a 20-year-old Forest Service test plot of CCA-treated 2 x 4's in Madison, WI., demonstrated the ability to release copper, chromium, and arsenic from CCA-treated wood in liquid culture. CCA-treated sawdust was exposed to this organism, which has been presumptively identified as Bacillus licheniformis. Analysis of the sawdust by atomic absorption spectroscopy revealed 80% reduction in copper and 43% reduction in arsenic when the sawdust was exposed to B. licheniformis in a standard mixed culture for 10 d compared to an untreated control. Enhanced release of metals was demonstrated when CCA-treated sawdust was exposed to the bacterium under continuous culture conditions in a chemostat. Steady-state growth of the bacterium under continuous culture conditions released 93% copper, 45% arsenic, and 6% chromium by weight from the sawdust. Exposure of CCA-treated wood to this isolate of B. licheniformis removed significant amounts of copper and arsenic from the wood.
C A Clausen

Effect of remediation on the release of copper, chromium, and arsenic from particleboard made from CCA treated wood
2001 - IRG/WP 01-50170
This study sought to determine the effect of remediation with oxalic acid (OA) extraction and Bacillus licheniformis fermentation on the release of copper, chromium, and arsenic from particleboard made from remediated wood particles and also investigates durability of the particleboard against white and brown- rot fungi. Particleboard samples were manufactured using untreated, CCA-treated, OA-extracted, and bioremediated southern yellow pine particles. Results shows that oxalic acid extraction and bioremediation by B. licheniformis significantly increased removal of elements from CCA-treated wood particles. The particleboards containing OA-extracted and bioremediated particles showed generally high leaching losses of remaining elements. Exposure of particleboard samples to decay fungi indicated that Gloeophyllum trabeum caused greater weight losses in all samples than Postia placenta. In general, leached samples from all particleboard types had greater weight losses than unleached samples. CCA particleboard samples were the most resistant to fungal degradation.
S N Kartal, C A Clausen

CCA removal from treated wood by chemical, mechanical and microbial processing
1998 - IRG/WP 98-50101-26
Most preservative-treated wood produced and consumed in the U.S. is treated with toxic inorganic compounds containing copper, chromium, and arsenic. Because chromated copper arsenate (CCA) is fixed to the wood, treated wood has not been considered toxic or hazardous and is currently landfilled. Increasing public concern about environmental contamination from treated wood combined with increasing quantities of CCA-treated wood nearing the end of it's service life has presented a recycling challenge for this fiber source. In this study, CCA-treated wood was processed by acid extraction, steam explosion and bacterial fermentation, and evaluated for removal of copper, chromium and arsenic. Copper was the least resistant to removal by these treatments, while chromium was the most resistant to removal. Grinding CCA wood chips into 20-mesh sawdust provided greater access to CCA components and greater removal of CCA metals by acid extraction and bacterial fermentation. Exposing CCA-treated sawdust to Bacillus licheniformis CC01 resulted in 91%, 15% and 45% removal of Cu (as CuO), Cr (as CrO3), and As (as As2O5), respectively. Eighty-one percent CuO, 62% CrO3, and 89% As2O5 was removed from CCA-treated sawdust by oxalic acid extraction alone. Combining acid extraction and bacterial fermentation resulted in similar rates of metal removal from CCA chips and sawdust; 80% reduction in CrO3, 100% removal of As2O5, 90 and 99% removal of CuO from chips and sawdust, respectively. Processing chips by steam explosion did not enhance removal of CCA components alone or in conjunction with acid extraction and bacterial fermentation. Grinding chips following acid extraction and prior to bacterial fermentation did not enhance the ability of the bacterium to remove metals from treated or steam exploded chips. The combination of acid extraction and bacterial fermentation was successful at removing 80-100 percent of the metals from CCA-treated wood sawdust and chips.
C A Clausen, R L Smith

Isolation and identification of bacteria from degraded wood - A progress report
1986 - IRG/WP 192
During attempts to isolate tunnelling bacteria in pure culture, physical separation from other bacteria was successfully achieved by the use of cellophane. Cellophane was used in liquid cultures as a substrate for tunnelling bacteria that were present in a mixture with other bacteria. By tunnelling into cellophane, TB were physically removed from contaminating bacteria which could then be removed by simple washing of the cellophane surface. The physically separated bacteria within the cellophane failed, however, to grow on various agar or liquid media. The reasons for this are discussed.
J A Drysdale, P J Ruland, J A Butcher

Isolation and identification of bacteria from CCA-treated eucalypt power transmission poles
1987 - IRG/WP 1317
Bacteria have been isolated from CCA treated Eucalyptus maculata poles which possessed characteristic bacterial decay patterns. Cultures were isolated on a number of different media which had been inoculated with a splinter of degraded wood. Primary tests indicated that most isolates belonged to the genera Pseudomonas and Bacillus. The species Pseudomonas cepacia was most frequently isolated.
G A Willoughby, A C Hayward, L E Leightley

Integrated protection of freshly sawn lumber using Bacillus subtilis and selected fungicide
1997 - IRG/WP 97-10235
Bioprotection against stain fungi has tremendous potential for reducing discoloration of freshly sawn wood while decreasing chemical consumption. Unfortunately, most bioprotectants appear to be unable to consistently perform under the array of conditions to which freshly sawn wood is exposed. While research is underway to understand the nature of the inconsistent performance, a more pragmatic approach to solving this problem is to alter the environment to more consistently favor the bioprotectant. One method for accomplishing this task is to apply low levels of biocides at the same time as the bioprotectant is applied. The biocide, although used below the threshold tor preventing fungal growth, should render the stain fungi less fit and, therefore, more susceptible to control. In this report, we evaluated the effect of 3 commonly used fungicide mixtures on the ability of B. subtilis to inhibit discoloration by a mixture of Ophiostoma perfectum, Phialphora spp., and Alternaria alternata on Pinus ponderosa sapwood under laboratory conditions. Bacillus subtilis provided poor control of discoloration. The addition of fungicide produced no enhancement of bioprotection. Evaluation of bacterial cultures containing this fungicide indicated that the chemicals had a profound effect on bacterial filters.
M E Mankowski, M Anderson, J J Morrell

Effect of nutrient regimes, temperature, pH, and wood sterilization method on performance of selected bioprotectants against wood staining fungi
1992 - IRG/WP 92-1551
The effect of nutrient regimes, incubation temperature, media pH, and wood sterilization method on performance of four potential bioprotectants (Pseudomonas putida, Pseudomonas cepacia, Bacillus subtilis, and Trichoderma harzianum) against wood staining fungi were evaluated using small ponderosa pine samples over a four week period. Incubation at 32°C resulted in slight increases in the degree of fungal stain, but the results were not consistent across treatment groups or bioprotectant species. Bioprotectant performance was altered through the use of different media, but, once again, the results were not consistent across all treatments for a given media. The pH of the media had a substantial effect on bioprotectant performance, with acidic conditions producing the poorest performance of bacterial bioprotectants and alkaline conditions reducing the protective effects of Trichoderma harzianum. The method of wood sterilization produced alterations in both the degree of staining and the composition of the microbial flora of the wood. Unsterile samples were stained to a greater degree than either autoclaved or irradiated specimens and the degree of bioprotection was generally lower. Delays in the interval between bioprotectant application and inoculation with wood staining fungi generally reduced the effectiveness of the bioprotectant, suggesting that bioprotection declined with incubation period. The results illustrate the complexity of developing bioprotectants which can effectively compete under the array of conditions common to freshly sawn lumber and suggest that considerable additional research will be necessary to more fully understand the conditions which assure successful protection.
J J Morrell, C M Secton

The association of bacteria with the increased permeability of water-stored spruce wood
1973 - IRG/WP 325
A microbiological investigation was undertaken to check our earlier work on patterns of bacterial counts and pH changes in water-stored wood. A survey of industrial activity was conducted upstream from the storage site with a view to explaining the existing bacterial flora. Further experiments were carried out with spruce bolts in enclosed tanks, using lake water with its natural bacterial flora and nutrients. The temperature was controlled and the water was circulated to ensure adequate oxygenation. Permeability and structural changes in the wood were examined at regular intervals. Isolates were made from the lake water and from the water-stored logs. The isolates made from the wood were examined for enzymatic activity and the growth patterns and the effect of temperature and pH on growth were studied. Some of these isolates were used in tank and sprinkler experiments. Bacterial counts, enzyme assays and permeability measurements were used to monitor the progress of these experiments.
J A Dunleavy, J P Moroney, S E Rossell

Study of new wood preservatives from biological origin and low toxicity against wood decay organisms (fungi and termites)
2006 - IRG/WP 06-10600
Wood as an organic material is likely to be attacked by living organisms if no protecting treatment is applied to improve its durability. The biological agents, which in Spain, due to its specific climatologic, cause major damage to wood, are the stain fungi, the rot fungi and the subterranean termites. The commercialisation of the products actually used to treat wood against fungi and to treat the buildings against termites, due to their toxicity and their persistence in the environment, could be prohibited in the near future. This ban would be a consequence of the 98/8/EC Directive (usually called Biocide Directive) transposed in the Spanish legislation in October 2002. The purpose of this work is to fill the need for new commercial products investigating for new products, which, due to their low toxicity for man and the environment, would be in compliance with the above quoted Directive. For controlling the stain and rot fungi, the efficacy of natural biocides used in agriculture and of new molecules isolated from fungi as Mycena species with ant fungi properties is being investigated. For controlling the termite population has been studied the effectiveness of bait treated with alive microorganisms (Beauvearia and Bacillus species). The results obtained up the moment, show good efficiency with this kind of products, as well as open a new line of research. In conclusion, the main possible advantage is to reduce the damages due to the action of wood destructive agents without producing detrimental effects on the environment.
M T Troya, M J Prieto, F Rubio, D Lorenzo, J J Teixidó